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United States Patent | 5,675,674 |
Weis | October 7, 1997 |
This invention is directed toward a fiber optic modulation and demodulation system, and more particularly directed toward a telemetry system for relaying signals from sensors in remote, harsh environments. Light is modulated using one or more optical reflective grating and piezoelectric crystal combinations, and demodulated using an interferometer system. The one or more modulators are driven by the responses of one or more sensors thereby modulating one or more carrier wavelengths of a carrier light source. The modulated light signal is transmitted from the sensor or sensors, over an optical fiber, to an interferometer which is used to demodulate the reflected signals and thereby determine the responses of one or more sensors. One embodiment of the invention set forth is that of a telemetry system linking sensors within a borehole to detection and processing equipment at the surface of the earth.
Inventors: | Weis; R. Stephens (Fort Worth, TX) |
Assignee: | RockBit International (Ft. Worth, TX) |
Appl. No.: | 518635 |
Filed: | August 24, 1995 |
Current U.S. Class: | 385/12; 250/227.18; 356/32; 385/1; 385/4; 385/37 |
Intern'l Class: | G02F 002/00 |
Field of Search: | 385/12,37,1,4,10,13,14,32,45 250/227.18,227.15,227.16 356/32 |
4761073 | Aug., 1988 | Meltz et al. | 356/32. |
4996419 | Feb., 1991 | Morey | 250/227. |